Ravina wants to cut a square cake using straight vertical cuts to make
five pieces of equal volume. If she makes the first cut from the cake's
center to the top left corner, where must she make the other cuts if they
all start from the cake's center?

Our teacher said that a piece of paper is a two-dimensional object
that has no height, but some of my classmates and I disagree. We think
a piece of paper still has a height, even if it is very, very, small,
and that it is therefore a three-dimensional object. Who's right?